#include "HsVersions.h"
-import HsSyn ( RuleDecl(..), RuleBndr(..), HsExpr(..), collectRuleBndrSigTys )
+import HsSyn ( RuleDecl(..), RuleBndr(..), collectRuleBndrSigTys )
import CoreSyn ( CoreRule(..) )
import RnHsSyn ( RenamedRuleDecl )
-import TcHsSyn ( TypecheckedRuleDecl, TcExpr, mkHsLet )
+import TcHsSyn ( TypecheckedRuleDecl, mkHsLet )
import TcRnMonad
import TcSimplify ( tcSimplifyToDicts, tcSimplifyInferCheck )
import TcMType ( newTyVarTy )
-import TcType ( TcTyVarSet, tyVarsOfTypes, tyVarsOfType, openTypeKind )
-import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs, tcVar )
+import TcUnify ( Expected(..) )
+import TcType ( tyVarsOfTypes, openTypeKind )
+import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs )
import TcMonoType ( tcHsSigType, UserTypeCtxt(..), tcAddScopedTyVars )
-import TcExpr ( tcMonoExpr )
-import TcEnv ( tcExtendLocalValEnv )
+import TcExpr ( tcCheckRho )
+import TcEnv ( tcExtendLocalValEnv, tcLookupGlobalId, tcLookupId )
import Inst ( instToId )
import Id ( idType, mkLocalId )
-import VarSet
import Outputable
\end{code}
tcRule (IfaceRule name act vars fun args rhs src_loc)
= addSrcLoc src_loc $
addErrCtxt (ruleCtxt name) $
- tcVar fun `thenM` \ fun' ->
+ tcLookupGlobalId fun `thenM` \ fun' ->
tcCoreLamBndrs vars $ \ vars' ->
mappM tcCoreExpr args `thenM` \ args' ->
tcCoreExpr rhs `thenM` \ rhs' ->
returnM (IfaceRuleOut fun' (Rule name act vars' args' rhs'))
-tcRule (IfaceRuleOut fun rule) -- Built-in rules come this way
- = tcVar fun `thenM` \ fun' ->
+tcRule (IfaceRuleOut fun rule) -- Built-in rules, and only built-in rules,
+ -- come this way. Usually IfaceRuleOut is only
+ -- used for the *output* of the type checker
+ = tcLookupId fun `thenM` \ fun' ->
+ -- NB: tcLookupId, not tcLookupGlobalId
+ -- Reason: when compiling GHC.Base, where eqString is defined,
+ -- we'll get the builtin rule for eqString, but eqString
+ -- will be in the *local* type environment.
+ -- Seems like a bit of a hack
returnM (IfaceRuleOut fun' rule)
tcRule (HsRule name act vars lhs rhs src_loc)
tcExtendLocalValEnv ids $
-- Now LHS and RHS
- getLIE (tcMonoExpr lhs rule_ty) `thenM` \ (lhs', lhs_lie) ->
- getLIE (tcMonoExpr rhs rule_ty) `thenM` \ (rhs', rhs_lie) ->
+ getLIE (tcCheckRho lhs rule_ty) `thenM` \ (lhs', lhs_lie) ->
+ getLIE (tcCheckRho rhs rule_ty) `thenM` \ (rhs', rhs_lie) ->
returnM (ids, lhs', rhs', lhs_lie, rhs_lie)
) `thenM` \ (ids, lhs', rhs', lhs_lie, rhs_lie) ->
-- RULE: forall v. fst (ss v) = fst v
-- The type of the rhs of the rule is just a, but v::(a,(b,c))
--
- -- We also need to get the free tyvars of the LHS; see notes
- -- below with ruleLhsTvs.
+ -- We also need to get the free tyvars of the LHS; but we do that
+ -- during zonking (see TcHsSyn.zonkRule)
--
forall_tvs = tyVarsOfTypes (rule_ty : map idType tpl_ids)
- `unionVarSet`
- ruleLhsTvs lhs'
in
-- RHS can be a bit more lenient. In particular,
-- we let constant dictionaries etc float outwards
new_id (RuleBndrSig var rn_ty) = tcHsSigType (RuleSigCtxt var) rn_ty `thenM` \ ty ->
returnM (mkLocalId var ty)
-ruleLhsTvs :: TcExpr -> TcTyVarSet
--- We need to gather the type variables mentioned on the LHS so we can
--- quantify over them. Example:
--- data T a = C
---
--- foo :: T a -> Int
--- foo C = 1
---
--- {-# RULES "myrule" foo C = 1 #-}
---
--- After type checking the LHS becomes (foo a (C a))
--- and we do not want to zap the unbound tyvar 'a' to (), because
--- that limits the applicability of the rule. Instead, we
--- want to quantify over it!
---
--- Fortunately the form of the LHS is pretty limited (see RnSource.validRuleLhs)
--- so we don't need to deal with the whole of HsSyn.
---
--- Uh oh! validRuleLhs only checks the function part of rule LHSs!
-
-ruleLhsTvs (HsPar e) = ruleLhsTvs e
-ruleLhsTvs (HsLit e) = emptyVarSet
-ruleLhsTvs (HsOverLit e) = emptyVarSet
-ruleLhsTvs (HsVar v) = emptyVarSet -- I don't think we need the tyvars of the Id
-
-ruleLhsTvs (OpApp e1 op _ e2) = ruleLhsTvs e1 `unionVarSet` ruleLhsTvs op
- `unionVarSet` ruleLhsTvs e2
-ruleLhsTvs (HsApp e1 e2) = ruleLhsTvs e1 `unionVarSet` ruleLhsTvs e2
-ruleLhsTvs (TyApp e1 tys) = ruleLhsTvs e1 `unionVarSet` tyVarsOfTypes tys
-ruleLhsTvs (DictApp e ds) = ruleLhsTvs e
-ruleLhsTvs (NegApp e _) = ruleLhsTvs e
-ruleLhsTvs (ExplicitList ty es) = tyVarsOfType ty `unionVarSet` ruleLhsTvs_s es
-ruleLhsTvs (ExplicitTuple es _) = ruleLhsTvs_s es
-
--- Type abstractions can occur in rules like
--- "foldr k z (build g) = g k z"
-ruleLhsTvs (TyLam tvs e) = ruleLhsTvs e `delVarSetList` tvs
-ruleLhsTvs (DictLam ids e) = ruleLhsTvs e
-ruleLhsTvs e = pprPanic "ruleLhsTvs" (ppr e)
-
-ruleLhsTvs_s es = foldr (unionVarSet . ruleLhsTvs) emptyVarSet es
-
ruleCtxt name = ptext SLIT("When checking the transformation rule") <+>
doubleQuotes (ftext name)
\end{code}
projects / ghc-hetmet.git / blobdiff